linux-kernel - [PATCH 3/4] firmware: qcom_scm: Refactor code to support multiple download mode

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Message-ID: <1676990381-18184-4-git-send-email-quic_mojha@quicinc.com>
Date:   Tue, 21 Feb 2023 20:09:40 +0530
From:   Mukesh Ojha <quic_mojha@...cinc.com>
To:     <agross@...nel.org>, <andersson@...nel.org>,
        <konrad.dybcio@...aro.org>
CC:     <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Mukesh Ojha" <quic_mojha@...cinc.com>
Subject: [PATCH 3/4] firmware: qcom_scm: Refactor code to support multiple download mode

Currently on Qualcomm SoC, download_mode is enabled if
CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT is selected. Refactor
the code such that it supports multiple download modes and
drop the config.

Signed-off-by: Mukesh Ojha <quic_mojha@...cinc.com>
---
 drivers/firmware/Kconfig    | 11 -----------
 drivers/firmware/qcom_scm.c | 45 +++++++++++++++++++++++++++++++++++++++------
 include/linux/qcom_scm.h    |  4 ++++
 3 files changed, 43 insertions(+), 17 deletions(-)

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index b59e304..ff7e9f3 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -215,17 +215,6 @@ config MTK_ADSP_IPC
 config QCOM_SCM
 	tristate
 
-config QCOM_SCM_DOWNLOAD_MODE_DEFAULT
-	bool "Qualcomm download mode enabled by default"
-	depends on QCOM_SCM
-	help
-	  A device with "download mode" enabled will upon an unexpected
-	  warm-restart enter a special debug mode that allows the user to
-	  "download" memory content over USB for offline postmortem analysis.
-	  The feature can be enabled/disabled on the kernel command line.
-
-	  Say Y here to enable "download mode" by default.
-
 config SYSFB
 	bool
 	select BOOT_VESA_SUPPORT
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index c376ba8..4975d3c 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -20,8 +20,43 @@
 
 #include "qcom_scm.h"
 
-static bool download_mode = IS_ENABLED(CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT);
-module_param(download_mode, bool, 0);
+static unsigned int download_mode;
+static struct qcom_scm *__scm;
+static void qcom_scm_set_download_mode(bool enable);
+static int set_dload_mode(const char *val, const struct kernel_param *kp)
+{
+	int ret;
+	int old_mode = download_mode;
+
+	ret = param_set_int(val, kp);
+	if (ret)
+		return ret;
+
+	switch (download_mode) {
+	case QCOM_DOWNLOAD_FULLDUMP:
+		if (__scm)
+			qcom_scm_set_download_mode(true);
+		break;
+	case QCOM_DOWNLOAD_NODUMP:
+		if (__scm)
+			qcom_scm_set_download_mode(false);
+		break;
+	default:
+		pr_err("unknown download mode\n");
+		download_mode = old_mode;
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct kernel_param_ops dload_mode_param_ops = {
+	.set = set_dload_mode,
+	.get = param_get_hexint,
+};
+module_param_cb(download_mode, &dload_mode_param_ops, &download_mode, 0644);
+MODULE_PARM_DESC(download_mode,
+		 "Download mode: 0x0=no dump mode (default), 0x10=full dump mode");
 
 #define SCM_HAS_CORE_CLK	BIT(0)
 #define SCM_HAS_IFACE_CLK	BIT(1)
@@ -70,8 +105,6 @@ static const char * const qcom_scm_convention_names[] = {
 	[SMC_CONVENTION_LEGACY] = "smc legacy",
 };
 
-static struct qcom_scm *__scm;
-
 static int qcom_scm_clk_enable(void)
 {
 	int ret;
@@ -435,8 +468,8 @@ static void qcom_scm_set_download_mode(bool enable)
 		}
 
 		ret = qcom_scm_io_writel(__scm->dload_mode_addr, enable ?
-				dload_addr_val | QCOM_SCM_BOOT_SET_DLOAD_MODE :
-				dload_addr_val & ~(QCOM_SCM_BOOT_SET_DLOAD_MODE));
+				((dload_addr_val & ~QCOM_DOWNLOAD_MODE_MASK) | download_mode) :
+				dload_addr_val & ~QCOM_DOWNLOAD_MODE_MASK);
 	} else {
 		dev_err(__scm->dev,
 			"No available mechanism for setting download mode\n");
diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
index f833564..dd6aced 100644
--- a/include/linux/qcom_scm.h
+++ b/include/linux/qcom_scm.h
@@ -14,6 +14,10 @@
 #define QCOM_SCM_CPU_PWR_DOWN_L2_OFF	0x1
 #define QCOM_SCM_HDCP_MAX_REQ_CNT	5
 
+#define QCOM_DOWNLOAD_MODE_MASK 0x30
+#define QCOM_DOWNLOAD_NODUMP	0x0
+#define QCOM_DOWNLOAD_FULLDUMP	0x10
+
 struct qcom_scm_hdcp_req {
 	u32 addr;
 	u32 val;
-- 
2.7.4